Revert "feat(fetch/network): add generic to json method"

[pavelfeldman]

Reverts #34091 - i rushed merging. It needs to be done via type overrides instead.

[github-actions]

Test results for "tests 1"

4 flaky

⚠️ [chromium-page] › page/page-event-request.spec.ts:138:3 › should report navigation requests and responses handled by service worker with routing @chromium-ubuntu-22.04-node20
⚠️ [firefox-page] › page/page-evaluate.spec.ts:403:3 › should throw for too deep reference chain @firefox-ubuntu-22.04-node18
⚠️ [installation tests] › playwright-cdn.spec.ts:41:7 › playwright cdn failover should work (https://cdn.playwright.dev) @package-installations-macos-latest
⚠️ [webkit-page] › page/page-set-input-files.spec.ts:245:3 › should upload large file with relative path @webkit-ubuntu-22.04-node18

37393 passed, 650 skipped
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Merge workflow run.